1. Field of the Invention
The present invention relates to an electronic card, and more particularly to a multi-functional electronic card capable of detecting removable cards.
2. Description of the Related Art
With the progress of the electronic technology, the electronic device is getting smaller. Examples of such electronic devices are notebook computers, palm computers, or personal digital assistants (PDAs). These small-sized electronic devices are portable and can provide processing capability to the users, thereby providing a great convenience to the users. However, since the size is small, such an electronic device is only provided with basic processing circuitry, while functions of some other circuit modules, such as external memories, modems, area network cards, etc., can only be realized by inserting corresponding electronic cards into the electronic device. These electronic cards can also be inserted to a personal computer for data exchange or storage.
Conventionally, the aforementioned electronic cards are connected to a host board adaptor (HBA) of the host system through a CF (compact flash) or PCMCIA interface. To make the host aware of whether the electronic card is inserted or removed, the PCMCIA/CF interface defines the card detecting pins CD#1 and CD#2, which are floating normally, and when the electronic card is inserted, are changed to be grounded. Therefore, when the HBA has detected that the CD#1 and CD#2 are grounded, it informs the host that a card has been inserted for performing a starting procedure. Accordingly, it is able to automatically detect the insertion/removal status of the electronic card.
To make the host device to be connected to more electronic peripheral cards with different interfaces, for example, Smart Media card, MMC (Multi-Medium Card) card, SD (Secure Digital) card, Memory Stick card, or PIC (Personal Information Carrier), a card adapter serves to connect these electronic cards to the PCMCIA/CF interface of the host device, as shown in FIG. 1. The card adapter 11 is provided with an elastic switch 13 in the card slot 12. One end of the elastic switch 13 is grounded, and the other end is connected to the CD#1 and CD#2 pins of the PCMCIA/CF interface 111 and further connected to the system high voltage when the card adapter 11 is inserted into the HBA 151 of the host system 15. When the electronic card, such as Smart Media card, MMC card, SD card, Memory Stick card, or PIC card has not been inserted into the card adapter 11, the elastic switch 13 is disconnected and thus the CD#1 and CD#2 pins are at high voltage level, so that the host system 15 does not supply power to the PCMCIA/CF interface. On the contrary, when the electronic card is inserted into the card adapter 11, the elastic switch 13 of the card slot 12 is pressed to be conducted so that the CD#1 and CD#2 pins are grounded, thereby pulling the voltage level from a high level down to a low level. The HBA 151 thus detects such an insertion status of the card, and then informs the host 152 to supply power of the PCMCIA/CF interface to perform a starting procedure.
The use of the above-described CD#1 and CD#2 pins can achieve the purpose of automatically detecting the insertion/removal status of the electronic card. However, in the practical application, if the electronic card is inserted arbitrarily, the power supplied to the PCMCIA/CF interface may be interrupted arbitrarily, which makes the PCMCIA/CF interface be in a tri-state and results in a system error. Besides, when the electronic card is removed and then is inserted again, the host system must re-supply power to the PCMCIA/CF interface and perform the starting procedure again. Therefore, the host system must wait for the power supply to be stable and the completion of the starting procedure for accessing the electronic card. Moreover, in realizing a multi-functional electronic card in which a plurality of functional devices are provided in one card and one of the functional devices is implemented as a removable device, it is possible that other functional devices will be powered off and cannot be used when this removable functional device is removed. Therefore, the conventional electronic cards still have many defects required to be improved.
Accordingly, the objective of the present invention is to provide a multi-functional electronic card capable of detecting removable cards to eliminate the problems in the conventional skill.
To achieve the objective, the multi-functional electronic card capable of detecting removable cards in accordance with the present invention includes: at least one functional device; a controller having a status register and a device detecting pin; a host interface for inserting into a host device, the host interface having a card detecting pin fixed at a level representing that a card is inserted; and a removable card interface for being inserted with a removable card with other functional device, the removable card interface having an elastic switch connected to the device detecting pin of the controller, the elastic switch being on or off due to insertion or removal of the removal card so as to change a level of the device detecting pin, wherein the controller detects event and status of a card insertion and removal by a level change of the device detecting pin for being set in the status register, and informs the host device through the host interface so that the host device reads the status register to determine whether the removable card is inserted or removed.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing.